The developments of refrigerators and freezer systems have resulted in the extensive use of different types of freons as the refrigerating medium. When repairing and scrapping small refrigerating and freezer systems recovery of the refrigerant has been ignored, since there is no method by means of which the refrigerant can be recovered easily and quickly and at relatively low costs. Instead, these freons have been quite simply released into the atmosphere. In the case of larger systems, attempts have been made, in comparable situations, to recover as much of the refrigerant as possible, with the aid of relatively expensive and unmanageable pistonless compressor pumps.
The recently recognized fact that freons have a harmful effect on the atmospheric protective ozone layer encircling the earth has led to a demand for a reduction in freon emissions into the atmosphere. This demand has led to the development of freon suction devices, or freon-exhausters, based on the use of piston compressors of the kind which are mass produced in large numbers, and therewith at relatively small costs, for use in conjunction with compressor driven refrigerators and freezers. These freon suction devices, however, are only suitable for extracting freon in gaseous form, since liquid freon cannot be compressed and consequently the compressor will be seriously damaged if liquid freon should enter a working piston compressor. Consequently, when emptying such refrigerating systems, which contain freon in both a liquid and a gaseous state in different parts of the system, it is recommended that the system is emptied from the gas side and that the liquid freon is permitted to pass to a gaseous state in the system during the process of emptying the system. Such an emptying process will take a long time to complete, however, and is not entirely safe, since there is always a risk that liquid freon will enter the pump and cause serious pump damage.